No-touch aorta off-pump coronary surgery: the effect on stroke

OBJECTIVE: Studies examining the neuroprotective effects of off-pump coronary artery bypass grafting have shown inconsistent results. Most studies, however, have not differentiated between clampless and clamp off-pump techniques. The aim of this study was to evaluate the effect of avoiding aortic manipulation on major neurologic outcomes after off-pump coronary artery bypass grafting. METHODS: A total of 700 consecutive patients undergoing multiple-vessel off-pump coronary artery bypass grafting between 2000 and 2003 were included. The 429 patients undergoing aortic no-touch technique were compared with 271 patients in whom partial aortic clamps were applied. The aorta was screened by manual palpation, and epiaortic ultrasonography was used selectively. RESULTS: The frequency of detected atherosclerotic aortic disease was higher in the no-touch group (17.4% vs 5.1%, P < .0001). No-touch revascularization was achieved with arterial conduits, arranged in T-graft or in situ configurations (50%). The respective graft/patient ratios were 2.5 +/- 0.6 and 2.6 +/- 0.6 in the side-clamp and no-touch groups ( P = .009); however, revascularization of the posterolateral myocardial territory was comparable (87% vs 90%, difference not significant). The incidence of stroke (0.2% vs 2.2%, P = .01) was significantly lower in the no-touch group (1/429). Logistic regression identified partial aortic clamping as the only independent predictor of stroke (odds ratio 28.5, confidence interval 0.22-333, P = .009), increasing this risk 28-fold. Peripheral vascular disease ( P = .068), diabetes ( P = .072), and history of stroke ( P = .074) trended toward stroke. CONCLUSIONS: Avoiding partial aortic clamping during off-pump coronary artery bypass grafting provides superior neurologic outcome. The results are reproducible and irrespective of the severity of aortic disease or the method of aortic screening. This technique is recommended whenever technically feasible.     

Expanding horizons of reconstructive microsurgery in Lebanon: Reconstruction of complex traumatic wounds with anterolateral thigh perforator flaps in paediatrics patients less than 10 years of age

Paediatric complex wounds pose a challenge to the reconstructive surgeon due to the intricacy of reconstructive options required. Developments in microsurgery and microsurgical technique have brought free tissue transfer ever closer to the comfort zone of the reconstructive surgeon for reconstruction of paediatric traumatic complex wounds. We present our experience of microsurgical reconstruction in Lebanon for complex traumatic wounds in paediatric patients under the age of 10 years using the free anterolateral thigh (ALT) flap. The ALT flap has proven its value as a safe, adaptable, and aesthetically acceptable reconstructive option in paediatric complex trauma.     

In vitro and in vivo effects of photodynamic therapy on murine malignant melanoma

Background: The role of photodynamic therapy (PDT) in the treatment of malignant melanoma is not well defined, nor is it known whether the dark melanoma cells absorb the light used in PDT. Methods: In vitro studies: 2×10⁵ B16 murine melanoma cells were incubated with aluminum phthalocyanine (AlpcS₄, 2.5 mg/kg) and were then subjected to photoradiation (50, 100 or 200 J/cm²). Viability was then assessed.In vivo studies: Histology: C57/B1 mice received 2×10⁵ B16 cells subcutaneously and were randomized into study (PDT) and three control groups. AlpcS₄ 2.5 mg/kg was injected intraperitoneally and the mice were exposed to light (100 J/cm²). After 24 hours they were sacrificed and underwent autopsies. Survival: 40 mice were randomized into PDT (40 J/cm²) and control groups and were monitored for 50 days. Tumor growth: 40 mice were randomized into one control and three treatment groups (PDT on day 3, 6, or 12 after injection with B16 cells), and were monitored for 50 days. Temperature: Tumor temperatures before and at the end of PDT were recorded. Results: In vitro studies: PDT caused a decrease in cell viability to 15.5±0.7%, 11.5±2.1%, and 1.5±0.7% (at 50, 100, and 200 J/cm², respectively;P<.001). A significant reduction in thymidine incorporation was noted at all energy levels.In vivo studies: Histology: PDT caused massive tumor necrosis. Survival: PDT prolonged the survival of mice (41±13.4 days) compared to controls (15.8±3.8 days,P<.001). Tumor growth: 31 days after injection with B16 cells, the tumor size was 2.6±0.3 cm in the control group and 1.6±0.2, 0.9±0.3, and 1.0±0.4 cm in the PDT groups (days 3, 6 and 12, respectively;P<.01). Temperature: PDT increased skin temperature to 42.8°C±1.3°C, 45.3°C±3.5°C, and 51.7°C±2.7°C at 40, 60, and 100 J/cm², respectively (P<.01). Conclusions: Photodynamic therapy was found to have significant effects in experimental melanoma in mice. The role of PDT in human melanoma remains to be studied.Presented at the 50th Annual Cancer Symposium of The Society of Surgical Oncology, Chicago, Illinois, March 20–23, 1997.     

Assessment of two thoracolumbar fracture classification systems as used by multiple surgeons

BACKGROUND: The reproducibility and repeatability of modern systems for classification of thoracolumbar injuries have not been sufficiently studied. We assessed the interobserver and intraobserver reproducibility of the AO (Arbeitsgemeinschaft für Osteosynthesefragen) classification and compared it with that of the Denis classification. Our purpose was to determine whether the newer, AO system had better reproducibility than the older, Denis classification. METHODS: Anteroposterior and lateral radiographs and computerized tomography scans (axial images and sagittal reconstructions) of thirty-one acute traumatic fractures of the thoracolumbar spine were presented to nineteen observers, all trained spine surgeons, who classified the fractures according to both the AO and the Denis classification systems. Three months later, the images of the thirty-one fractures were scrambled into a different order, and the observers repeated the classification. The Cohen kappa (kappa) test was used to determine interobserver and intraobserver agreement, which was measured with regard to the three basic classifications in the AO system (types A, B, and C) as well as the nine subtypes of that system. We also measured the agreement with regard to the four basic types in the Denis classification (compression, burst, seat-belt, and fracture-dislocation) and with regard to the sixteen subtypes of that system. RESULTS: The AO classification was fairly reproducible, with an average kappa of 0.475 (range, 0.389 to 0.598) for the agreement regarding the assignment of the three types and an average kappa of 0.537 for the agreement regarding the nine subtypes. The average kappa for the agreement regarding the assignment of the four Denis fracture types was 0.606 (range, 0.395 to 0.702), and it was 0.173 for agreement regarding the sixteen subtypes. The intraobserver agreement (repeatability) was 82% and 79% for the AO and Denis types, respectively, and 67% and 56%, for the AO and Denis subtypes, respectively. CONCLUSIONS: Both the Denis and the AO system for the classification of spine fractures had only moderate reliability and repeatability. The tendency for well-trained spine surgeons to classify the same fracture differently on repeat testing is a matter of some concern.     

Relevance of Toll-like receptor-4 polymorphisms in renal transplantation

BACKGROUND: Polymorphisms in Toll-like receptor-4 (TLR4) have been reported to be associated with a blunted immune response to microbial pathogens, as well as a decreased risk of atherosclerosis in the general population. We assessed the impact of the two TLR4 variants on the risk of severe infection, the incidence of acute rejection, and the occurrence of atherosclerotic complications in renal transplant recipients (RTR). METHODS: TLR-4 polymorphisms were assessed in a cohort of 238 RTR. Post-transplant atherosclerotic events, acute rejection, severe bacterial infection, cytomegalovirus (CMV) disease, and opportunistic infections were evaluated as outcomes. RESULTS: The patients were followed for a mean duration of 95 +/- 29 months after transplant. TLR4 polymorphism was observed in 27 (11.3%) RTR. Subjects with TLR4 polymorphisms were less likely to experience post-transplant atherosclerotic events (RR 0.44; 95% CI 0.21 to 0.93; P= 0.02) and acute rejection (RR 0.41; 95% CI 0.30 to 0.83; P= 0.01), but presented severe bacterial infections (RR 1.33; 95% CI 1.12 to 1.67; P= 0.01) and opportunistic infections (RR 3.03; 95% CI 1.72 to 8.29; P= 0.008) more frequently. TLR4 polymorphism was marginally associated with CMV disease (RR 1.47; 95% CI 0.95 to 2.64; P= 0.08). CONCLUSION: RTR with TLR4 polymorphism present a lower risk of post-transplant atherosclerotic events and acute allograft rejection, but experience severe infectious episodes more frequently. This subset of RTR may benefit from a less potent immunosuppression regimen, along with increased preventive measures against infectious agents.